The automotive industry in India has been undergoing a significant transformation in recent years, particularly with the implementation of stricter emission standards. The transition from Bharat Stage 4 (BS4) to Bharat Stage 6 (BS6) emission norms marked a major milestone in the country’s efforts to combat air pollution and promote cleaner, greener vehicles. But what exactly are these emission standards, and how do BS4 and BS6 differ?
In this blog, we will explore the differences between BS4 and BS6 emission standards, why this transition was necessary, and how it impacts vehicles, the environment, and consumers.
What Are Emission Standards?
Emission standards are regulations that set specific limits on the amount of pollutants that vehicles can emit. These standards are critical in controlling air pollution, particularly in urban areas where vehicle emissions are a major contributor to air quality issues. In India, these standards are known as Bharat Stage (BS) norms, which are similar to the European emission standards.
- Bharat Stage 1 (BS1): Introduced in 2000, BS1 was the first set of emission norms in India.
- Bharat Stage 2 (BS2): Implemented in 2001, with stricter limits on pollutants like carbon monoxide (CO) and hydrocarbons (HC).
- Bharat Stage 3 (BS3): Introduced in 2005, further reducing permissible emission levels.
- Bharat Stage 4 (BS4): Implemented nationwide in 2017, marked a significant reduction in allowed emissions, particularly NOx and particulate matter (PM).
- Bharat Stage 6 (BS6): Introduced in April 2020, skipped BS5 entirely, and set much stricter limits on emissions, with advanced technologies to reduce pollutants.
Key Differences Between BS4 and BS6
The shift from BS4 to BS6 represents a leap in terms of emission control, with several critical differences between the two standards. Let’s dive into the major differences:
1. Emission Limits
The most significant difference between BS4 and BS6 norms is the emission limits imposed on various pollutants.
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BS4 Emission Limits:
- Nitrogen Oxides (NOx): Diesel vehicles under BS4 norms were allowed to emit up to 250 mg/km.
- Particulate Matter (PM): BS4 permitted up to 25 mg/km of PM from diesel vehicles.
- Carbon Monoxide (CO): The limit for CO was higher, allowing more of this harmful pollutant.
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BS6 Emission Limits:
- Nitrogen Oxides (NOx): BS6 mandates a reduction of nearly 70% for diesel vehicles, with a limit of 80 mg/km.
- Particulate Matter (PM): BS6 requires a reduction in PM emissions by 80%, with a limit of 4.5 mg/km for diesel vehicles.
- Carbon Monoxide (CO): The limits for CO have also been tightened under BS6 norms.
Impact: The stricter emission limits under BS6 result in significantly cleaner exhaust emissions, leading to reduced air pollution and improved public health.
2. Fuel Quality
Another critical difference between BS4 and BS6 is the quality of fuel required.
- BS4 Fuel: BS4 fuel has a sulfur content of 50 parts per million (ppm).
- BS6 Fuel: BS6 fuel has a much lower sulfur content of 10 ppm, which is essential for the proper functioning of BS6-compliant engines and their emission control systems.
Impact: The low sulfur content in BS6 fuel helps reduce sulfur dioxide emissions, which are a major contributor to air pollution and acid rain. It also prevents damage to the advanced emission control systems used in BS6 vehicles.
3. Advanced Emission Control Technologies
To meet the stringent BS6 norms, vehicles are equipped with advanced emission control technologies that were not required under BS4.
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BS4 Technologies:
- Diesel Oxidation Catalyst (DOC): Commonly used to reduce CO and HC emissions.
- Exhaust Gas Recirculation (EGR): Used to reduce NOx emissions by recirculating a portion of the exhaust gases back into the engine cylinders.
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BS6 Technologies:
- Diesel Particulate Filter (DPF): Filters out particulate matter (soot) from the exhaust gases, significantly reducing PM emissions.
- Selective Catalytic Reduction (SCR): Uses a urea-based solution (AdBlue) to convert NOx into harmless nitrogen and water, reducing NOx emissions by up to 90%.
- Lean NOx Trap (LNT): Used in some vehicles to reduce NOx emissions further.
Impact: These advanced technologies ensure that BS6 vehicles emit far fewer pollutants than their BS4 counterparts, making them much more environmentally friendly.
4. On-Board Diagnostics (OBD)
On-Board Diagnostics systems monitor the vehicle’s emissions in real-time, ensuring that they remain within the permissible limits.
- BS4 OBD: Basic OBD systems were used, primarily to detect faults in the emission control system and alert the driver.
- BS6 OBD: BS6 mandates more advanced OBD systems that not only detect faults but also provide real-time data on emissions, helping to maintain compliance with the stringent BS6 norms throughout the vehicle’s lifespan.
Impact: The enhanced OBD systems in BS6 vehicles provide better monitoring and maintenance of emission standards, ensuring long-term compliance and reducing the environmental impact of older vehicles.
5. Cost Implications
The implementation of BS6 norms has also impacted the cost of vehicles.
- BS4 Vehicles: Comparatively less expensive due to simpler emission control technologies and less stringent fuel requirements.
- BS6 Vehicles: Generally more expensive due to the advanced emission control technologies and the need for high-quality, low-sulfur fuel.
Impact: While BS6 vehicles are costlier, the benefits in terms of reduced emissions, better fuel efficiency, and long-term compliance make them a better investment for both the environment and consumers.
Why the Transition Was Necessary
The move from BS4 to BS6 was driven by the need to reduce air pollution and its associated health risks. India is home to some of the most polluted cities in the world, and vehicle emissions are a significant contributor to poor air quality. The stricter BS6 norms are designed to address this issue by reducing harmful pollutants, thereby improving air quality and public health.
Environmental Benefits
The BS6 norms are expected to lead to a significant reduction in the levels of harmful pollutants like NOx and PM, which are known to cause respiratory problems, cardiovascular diseases, and other health issues. By reducing these emissions, BS6 vehicles contribute to a cleaner environment and healthier living conditions.
Global Compliance
The BS6 emission standards are on par with the Euro 6 norms, making Indian vehicles compliant with global standards. This alignment not only helps improve air quality domestically but also enhances the competitiveness of Indian automotive manufacturers in the international market.
Conclusion: AutoDukan - Your Partner in Emission Compliance
Understanding the differences between BS4 and BS6 is crucial for making informed decisions about your vehicle. Whether you’re looking to upgrade to a BS6-compliant vehicle or need parts and accessories for your existing vehicle, AutoDukan has you covered.
At AutoDukan, we offer a wide range of BS6-compliant products that ensure your vehicle meets the latest emission standards. From advanced emission control systems to high-quality BS6 fuel and accessories, we have everything you need to keep your vehicle running smoothly and efficiently.
Visit AutoDukan today to explore our selection of products and services, and stay ahead of the curve in emission compliance. Trust AutoDukan to be your go-to source for all your automotive needs, ensuring that your vehicle not only performs at its best but also contributes to a cleaner, greener future.
Great blog, very informative!